Top European officials hashed out an accord in Monday's early hours that probably saved Cyprus from becoming the first country to crash out of the euro, but at the price of deepening the political mistrust between the strong economies of Europe's north and the weaklings of the south.

The often-chaotic negotiations that led to the agreement have shattered the calm in the euro zone. The bitterness over the Cyprus mess—deeper initially than at low points in Greece's extended financial turmoil—could leave lasting damage and...